ROOT-CANAL PREPARATION USING THE 2ND-HARMONIC KTP-YAG LASER - A THERMOGRAPHIC AND SCANNING ELECTRON-MICROSCOPIC STUDY

Thermal and microstructural events resulting from KTP laser use during root canal preparation were investigated in 30 extracted single-roote d human teeth. In the first section of this study, thermal events occu rring on the root surfaces of 18 teeth during and after exposure of th e root canal were measured using thermography. A variety of parameters were used to determine settings that would be effective without causi ng thermal damage to the periodontal ligament. In the second section o f the study, root canals of 12 teeth exposed to KTP laser irradiation at parameters derived from section 1 were evaluated using Scanning ele ctron microscopy. KTP laser application at a power setting of 3 W, an exposure time of 2 s, and a frequency of 5 Hz, applied five times, rem oved smear layer and debris from the root canal surface at temperature s below the thermal injury threshold for periodontal tissue.